If you're curious why the Superman isn't good at yaw, just take a picture of yourself from the direction of the wind at some yaw angle. Since you're leaning so far forward, at any angle other than straight on, you'll look wide to the wind. This not only increases your area, but also drag coefficient since you're forcing the air to try to go around and "stick" to your body, which it can't do, leaving a big wake. Basically always think about the wind, it always tries to be parallel to your body and when it can't change direction that fast, it'll separate leaving a wake and creating drag.
It's the same reason Kamm tail drag results are presented at some yaw angle - they're less aerodynamic than the completed tail straight on, but will be better at yaw since they're shorter.
In terms of optimizing position, it's all about the race. You would technically want the position that gives you the least yaw angle weighted drag, with the weights depending on wind angle expected on a statistical basis.
I like analyzing things -
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